Dazed and Confused

[Tim Rogers]

Mark wrote (and I snipped):

>>About 6 weeks ago, Eric and I reset the base idle and timing on my '91
Classic.
About 2 weeks later, we pulled and cleaned the tb. After that I had to reset
my base idle because it had jumped to 1500rpm after the tb cleaning.

Today, I went to Eric's and he used his new nprobe on the car to check how
it is functioning. The idle was jumpy, btwn 850-950rpm, and the timing was
at 15 degrees. Found out my engine is running hot, too. I changed the
coolant at the same time we did the tb. Bled everything correctly, twice.
It's at 200 when it should be at 180.<<

Lets look at the Temp. issue first.  It could be as simple as a thermostat
or the temperature sensor going bad.  If its the Temp. sensor, you're
probably not running too warm, you're just reading too warm.
I would change the thermostat first (they do go bad after a while) and if
its still indicating warmer than usual, try a new temp. sensor.

For the idle, I just helped a friend who had idle issues on his recently
purchased 240SX.
We tried setting the base idle, but it kept dive bombing, so I sprayed an
entire can of Pep Boys generic Throttle Body Cleaner past the throttle
plate, aiming towards the far end of the plenum where the Idle Air Control
Valve is located.  I also sprayed some into the hose that leads to the IACV.
This is the middle (in both size and placement) of the hoses that start on
the firewall side of the intake hose.
This stuff worked like a charm and allowed the engine to run pretty well
while I was spraying it, as opposed to some brands that seem to try to stop
the motor from running.

If this does not help, you could look to see if your MAF needs to be
regrounded, or you could have an EGR issue.  See SE-R.net for more info on
that...

Tim